Introduction. The present study assessed Pseudomonas aeruginosa surface characteristics, motility and adhesion properties under the influence of 1-[4-(1,1,3,3-tetra methyl butyl) phenoxy]-3-(N-benzyl hexa methylene iminium)-2-propanol chloride (KVM-194). Material and methods. The clinical strain P. aeruginosa 449 was used in the study. The cell surface hydrophobicity (CSH) was evaluated by adhesion to solvent (MATS test). Swimming, swarming and twitching motility of P. aeruginosa were studied by standard methods in media with different agar contents. Cells ability to adhere to polystyrene was assessed by the Christensen method. The effect of KVM-194, meropenem and ciprofloxacin on hydrophobicity and motility was evaluated both at 0.5 or 2.0 minimal inhibitory concentrations (MIC), while on adhesion abilities – only 0.5×MIC. Results. It was shown that 0.5× MIC KVM-194 reduced CSH of P. aeruginosa (by 16%, p˂0.05), affected swimming motility, and decreased its adhesion to polystyrene. The most pronounced changes in adhesion properties were recorded after 3-5 hours of pre-treatment with this compound. Moreover, it was proven that sub-MICs of meropenem and ciprofloxacin did not alter bacterial cells hydrophobicity and had no significant influence on P. aeruginosa motility and adhesion properties. Conclusions. The present study suggested that KVM-194 affected the initial steps of   P. aeruginosa biofilm formation and thus had tremendous potential for new antibiofilm agents’ development.

Staphylococcus aureus is a widespread opportunistic pathogen, causing community-acquired and nosocomial infections with both acute and chronic recurrent courses. The process of chronicity of the disease is provided by biofilms. Features of the structure and functioning of biofilms, in particular the presence of matrix, quorum sensing systems, persistent cells, and efflux pumps, provide microbial communities with resistance to antimicrobial drugs under their action in therapeutic concentrations. The insufficient eff ectiveness of modern antimicrobial chemotherapy against biofi lm microorganisms indicates the urgency of the problem to search for compounds with antibiofilm activity that can affect various stages of the biofilm formation and the formed biofilm. The aim of the study is to establish the antibiofilm activity of 4-(adamantyl-1)-1-(1-aminobutyl) benzol against methicillin-resistant S. aureus (MRSA) and to determine the mechanism of its action. Methods. The ability of adamantane-containing compound 4-(adamantyl-1)-1-(1-aminobutyl) benzol (AM-166) to prevent biofilm formation and destroy the formed biofilm of S. aureus was investigated on polystyrene plates by the sorption of gentian violet on its structures followed with desorption of the dye into the organic solvent. The viability of S. aureus cells at the first stage of biofilm formation and in the composition of mature biofilms was evaluated using specific dyes for living (acridine orange) and non-viable (propidium iodide) cells. Detection of genes responsible for antibiotic resistance and biofi lm formation was performed by the polymerase chain reaction (PCR) with detection of PCR products in agarose gel. Evaluation of the effect of AM-166 on the expression of genes regulating the biofilm formation (ica, agrA, sarA, and sigB) was investigated by the real-time PCR and semi-quantitative PCR. Results. It was found that the compound AM-166 shows activity against S. aureus biofilm formation. The most pronounced effect was registered at a concentration of 5.0 minimum inhibitory concentration (MIC) (92.3%.) Under the action of AM-166 on the formed 2-day biofilms, their destruction was marked: the biomass decreases by 30.9% at 5.0 MIC. According to the results of fluorescence microscopy, the adamantane derivative at 5.0 MIC helps to reduce the number of viable cells at different stages of formation of the S. aureus biofilm. The results of molecular genetic studies indicate that the ica gene expression is significantly inhibited by the action of subinhibitory concentrations of the compound AM-116. No significant changes in the expression of sarA, agrA, and sigB genes were registered. Conclusions. Experiments on the effect of adamantane derivative on S. aureus biofilms showed that the most pronounced activity of AM-116 was observed at the stage of biofilm formation, as evidenced by the inhibition of transcriptional activity of the ica gene responsible for early stages of the biofilm formation, in particular the adhesion of planktonic cells to the substrate.

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